The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that does not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted to be prior art against the present disclosure.
High-speed Ethernet communication is commonly used for computer networking and in recent years has been adapted for use in automotive environments. For example, an automotive cable is used to connect sub-systems of an automobile, including for example engine, braking, steering, safety and various sensor sub-systems. Such cable communication connection is usually subject to stringent electromagnetic interference (EMI) requirements in order to provide safe and efficient transfer of data among the various automobile sub-systems. Characteristics of the cable connection, such as the cable length, are measured to assess the performance of the connection.
Existing methods to measure a cable length include using time domain reflection (TDR) or digital signal processing (DSP) based echo response. In these methods, the measurement resolution is highly dependent on the sampling rate (usually equivalent to the data symbol rate) or the pulse width of the incident signal that is sent to generate a reflection or echo. When the sampling rate, i.e., the transmission data symbol rate, is low, the measurement resolution of the cable length is usually unsatisfactory.